Dengue is the fastest spreading,mosquito-borne viral infectious disease worldwide,with remarkable morbidity and mortality.In the past decades,profound contributions have been made towards understanding its epidemiology,including disease burden and distributions,risk factors,and control and prevention practices.Dengue continues to disseminate to new areas,including high latitude regions,and a new serotype (dengue virus serotype 5) has been identified.Vaccine research has made new progress,in which the licensed yellow fever and dengue virus quadrivalent chimeric vaccine is now under further safety assessment.In disease surveillance,because of its operational simplicity,rapidity,capability,and utility as an indicator of disease severity,dengue virus NS1 antigen detection has great promotion and application value among primary health care institutions.Vector control progress has driven new breakthroughs in biotechnology,including Wolbachia-infected Aedes and genetically modified Aedes.Both Aedes variants have been used to block transmission of the dengue virus through population replacement and suppression.In the future,vector control should still be pursued as a key measure to prevent transmission,along with anti-viral drug and vaccine research.
Background:Dengue was regarded as a mild epidemic in China's Mainland transmitted by Aedes albopictus.However,the 2014 record-breaking outbreak in Guangzhou could change the situation.In order to provide an early warning of epidemic trends and provide evidence for prevention and control strategies,we seek to characterize the 2014 outbreak through application of detailed cases and entomological data,as well as phylogenetic analysis of viral envelope(E)gene.Methods:We used case survey data identified through the Notifiable Infectious Disease Report System,entomological surveillance and population serosurvey,along with laboratory testing for IgM/IgG,NS1,and isolation of viral samples followed by E gene sequencing and phylogenetic analysis to examine the epidemiological and molecular characteristics of the outbreak.Results:The 2014 dengue outbreak in Guangzhou accounted for nearly 80%of total reported cases that year in China's Mainland;a total of 37,376 cases including 37,340 indigenous cases with incidence rate 2908.3 per million and 36 imported cases were reported in Guangzhou,with 14,055 hospitalized and 5 deaths.The epidemic lasted for 193 days from June 11 to December 21,with the highest incidence observed in domestic workers,the unemployed and retirees.The inapparent infection rate was 18.00%(135/750).In total,96 dengue virus 1(DENV-1)and 11 dengue virus 2(DENV-2)strains were isolated.Phylogenetic analysis indicated that the DENV-1 strains were divided into genotype I and V,similar to the strains isolated in Guangzhou and Dongguan in 2013.The DENV-2 strains isolated were similar to those imported from Thailand on May 11 in 2014 and that imported from Indonesia in 2012.Conclusions:The 2014 dengue epidemic was confirmed to be the first co-circulation of DENV-1 and DENV-2 in Guangzhou.The DENV-1 strain was endemic,while the DENV-2 strain was imported,being efficiently transmitted by the Aedes albopictus vector species at levels as high as Aedes aegypti.
Lei LuoLi-Yun JiangXin-Cai XiaoBiao DiQin-Long JingSheng-Yong WangJin-Ling TangMing WangXiao-Ping TangZhi-Cong Yang
